The Gemini 500R monolight features the ability to be powered by AC circuitry in the studio, or by the award winning Travelpak battery unit while on location. In addition to being PocketWizard compatible, the 500R boasts a range of features designed to offer photographers not only ultimate freedom, but unmatched power, durability, and control. Simplicity is the key with Bowens Gemini flash units, with digitally accurate control made easy without a confusing menu system. Just turn one dial to adjust the flash power in full f stops, and the other for 1 10th f stops to covering a range of five stops of power from 500W s to 15W s. The Gemini 500R can be powered by AC circuitry in the studio, and when you want to go out on location, your studio quality lighting can go along. Gemini monolights can be powered by the optional Bowens Travelpak battery system sold separately which is able to provide power for two Gemini units. Using the 500R with the Small Travelpak will provide up to 150 full power flashes per charge double with the Large Travelpak . The built in photocell on the Gemini 500R has a smartcell option to enable pre exposure flashes to be ignored. This feature can be used for exposure measurement and or red eye reduction. The smartcell allows the Gemini unit to be synchronized to the camera shutter on the 1st, 2nd, 3rd or 4th flash. For traditionalists who like to have a physical connection between the camera and monolight, the Gemini has a 1 4 jack socket, and the low 5V sync means that your camera 39;s sensitive circuitry is safe. Bowens products have always been acclaimed for build quality and durability. The Gemini 500R is no different. The tough metal body protects the sophisticated circuitry and high powered capacitors from the knocks and bumps which naturally occur in busy studios and during transportation. It is for this reason that Bowens lights are so popular all around the world.